Fans



Nov. 10, 1959 K. M. GANGER EI'AL 2,912,159

FANS

Filed March 19, 1956 2 Sheets-Sheet 1 FIG-1 4 35 32 V FIG-3 9 83 I 0 1 0A 2o 51 M FIG -4 16 INVENTORS KARL M.GANGER a 15 BY WIILLIAM awaunmsATTORNEYS Nov. 10, 1959 K. M. GANGER ETAL 2,912,159

FANS

Filed March 19, 1956 2 Sheets-Sheet 2 FIG-6 FIG-5 IN V EN TORS KARL M.SANGER a BY WILLIAM H.WENTLING 9 v' QM y? ATTORNEYS FANS Karl M. Gangerand William H. Wentling, Dayton, Ohio, assignors to The Lau BlowerCompany, Dayton, Ohio, a corporation' of Ohio Application March 19,1956, Serial No. 572,527 '5 Claims. Cl. 230-259 This invention relatesto fans.

The invention has special relation to fans of the portable type suitablefor use in the home and other buildings for purposes of ventilation andcirculation of air. For example, the fans. of the invention areespecially suited for temporary mounting in a window to serve either forexhausting air from the room or for drawing cool outside air into theroom.

It is a primary object of the invention to provide a ventilating fanwhich incorporates a reversible drive motor to make possible reversal ofthe air flow from the fan without changing its physical position, andwhich also incorporates blades of special configuration to giveeflicient operation in both directions of rotation and to permiteffective cooling of the drive motor in both direc tions of rotation.

An additional object of the invention is to provide a fan bladeespecially adapted for use in a reversible fan togive efiicientoperation in both directions of rotation of the blade assembly and whichincludes edge portions curved in opposite directions to servealternatively as leading andtrailing edges and also to promote a coolingflow of air in close proximity to the drive motor in both directions ofrotation of the fan.

A further object of the invention is to provide a fan blade as outlinedabove wherein the curved portions of the blade are provided withintegral ribs or beads extending perpendicularly to the axes ofcurvature thereof to stiffen the curved blade portions for maintainingthe curved configurations thereof.

It is also an object of the invention to provide a ventilating fan whichincorporates a thermostatic switch for turning the fan motor on and offat predetermined high and low temperatures respectively, and which alsoincorporates a signal effective to give continuous indication of theopen and closed positions of the main control switch of the fanindependently of the position of the thermostatic switch.

Additional objects and advantages of the invention will be apparent fromthe following description, the accompanying drawings and the appendedclaims.

In the drawings- Fig. 1 is a view in front elevation showing a fanconstructed in accordance with the invention;

Fig. 2 is an enlarged fragmentary sectionon the line 22 of Fig. 1;

Fig. 3 is a wiring diagram for the fan of Fig. 1;

Fig. 4 is an enlarged detail section on the line 4-4 of Fig. 1;

Fig. 5 is an enlarged view in vertical section through the casing of thefan of Fig. 1 as indicated by the line 5-5 of Fig. 1;

Fig. 6 is a detail view in front elevation of the blade assembly of thefan of Figs. 1 and 4;

Fig. 7 is an outer end elevation of one of the fan blades of Fig. 6;

Fig. 8 is a detail elevational view illustrating one of the blades inFigs. 6 and 7; and

2 Fig. 9 is an enlarged fragmentary section onthe line 9,-9 of Fig. 8.

Referring to the drawings, which illustrate a preferred embodiment ofthe invention, the casing 10 is of gen erally rectangular annular shape.A panel -11 of generally channeled configuration is mounted within. thecasing 10 along one of theshorter sides and at the front thereof, andasimilar panel 12 is mounted at the back of the casing. These panels areproportioned to cover a fraction ofthe casing such that the remainingopen area is approximately square, and the venturi panel 13 is mountedin the casing with the opening therethrough centered on the open part ofthe casing. A bracing strip 14 is connected between the panels 11 and 12and the venturi panel 13 as shown in Fig. 2 to provide a rigid assembly.

A carrying handle 15 is mounted at the top of the casing in centeredrelation along the longer side in conjunction with a decorative andstiffening cap 16. The handle 15.normally rests in a retracted positionas shown in Fig. '4, which is provided for by the bolts 17 which slidein rubber grommets 18. When it is desired to use the handle to lift thefan, the handleis raised to the dotted position shown in Fig. 4.

A drive motor 20 is mounted within the casing 10 in centered relationwith the opening through the venturi panel 13 by means of a bracket 21which extends vertically between the top and bottom of the casing. Themotor shaft 22 projects from the front of the motor and supports theblade assembly which comprises a spider 23 secured to the shaft by a hub24 and set screw and carrying three blades 25. A grill 26 is shown asmounted by brackets 27 on the front of the casing to guard the front ofthe fan, and a similar grill maybe mounted at the back of the casing.

The panel 11 provides a mounting for the several controls for the fanwhich are shown in the wiring diagram in Fig. 3. The power leads L-1 andL-2 are contained within a conventional electric 'cord.30. The maincontrol switch 31 is shown as having an Off and three On positions toprovide three selective speeds for the fan. A thermostatic switch 32 isconnected in series with con: trol switch 31 and the motor, and thisthermostatic switch is designed to close the circuit between the mainswitch 31 and the motor at a predetermined high tem' perature forstarting the fan and to open at a predeter: mined low temperature inorder to shut off the fan.

In use with this arrangement as described up to this point, the fan maybe mounted in a window and turned on during a summer night for thepurpose of cooling a bedroom. If the room temperature drops sufficientlyto permit the fan to be turned off without interfering with the comfortof the sleeper, the thermostatic switch accomplishes this result. If thetemperature should subsequently rise, the fan would then again be turnedon, and so forth. However, it is possible that the fan will not berunning in the morning when the user rises and that the user may closethe window without remembering to open the main switch 31. Then later inthe morning when the temperature in the room rises, the thermostaticswitch would, again start the fan, and if the window were closed, or ifthe occupants were not in the building, there would be no reason foroperating the fan.

The present invention includes a provision directed to preventing-theundesirable result just discussed by estab-' lishing a continuous signalof the position of the control switch 31. This signal is shown as alight 33 mountedat the top of the panel 11 and connected in series withthe main switch 31'but in parallel wtih the motor and thermostaticswi'tch 32 so that the light 33 will be energized whenever theswitch 31 is closed irrespective of the position of the thermostaticswitch 32. Therefore, in the instance described in the precedingparagraph, on rising in the morning the user of the fan will see thatthe light 33 is lighted and will therefore be reminded to turn the mainswitch 31 to its Off position before leaving the fan for the day.

In addition to the main and thermostatic switches, the motor 20 isprovided with a reversing switch 35 which is also mounted on the panel11. Satisfactory results have been obtained in use with the motor 20being of the shaded pole type provided with alternatively usable shadingcoils adapted to be selectively open circuited by the switch 35 asindicated in Fig. 3, and also with the motor 20 of the permanent splitcapacitor type provided with the same type of reversing switch 35. Thisarrangement provides for reversal of the direction of flow of air fromthe fan without changing the position of the casing or changing theposition of the fan itself within the casing.

The fan blades 25 are of special configuration and characteristics whichprovide several practical advantages. Referring particularly to Figs.6-9, the main central area 40 of each blade 25 is essentially flat, andit extends from the inner edge of the blade and includes a major portionof the outer edge of the blade. This'central blade area 40 is mounted onthe spider 23 in inclined relation with a radial plane through motorshaft 22 such that when the direction of rotation of the blade assemblyis clockwise as viewed in Figs. 1 and 6, the resulting air flow will betoward the front of the fan. The portion 41 of each blade will thereforebe the leading edge portion, and it is cylindrically curved with respectto the portion 40 along the line 42 and toward the back of the fan. Thesimilar portion 44 along the opposite edge of the blade is curvedforwardly along the line 43. Both of these curved portions 41 and 44also incorporate integrally formed ribs or beads which extend out to theedge of the blade from the flat portion 40 and substantiallyperpendicularly to the lines 42 and 43 respectively.

As shown in Figs. 6 and 9, the inner edge of each 7 blade 25 includes amiddle section 46 of substantial extent which is arcuately curved to besubstantially concentric with the axis of the motor shaft 22 in themounted position of the blade. In addition, the inner edge sections 47and 48 of each blade are curved in the opposite direction from thesection 46 to provide lobe or corner-like portions on the blade in theareas thereof nearest to the motor 20. These lobe portions form themajor areas of the respective side portions 41 and 44, and they haveimportant actions in the operation of the fan.

Thus when the fan is rotating in clockwise direction as viewed in Figs.1 and 6, the surface speed of the blade is at a maximum at its radiallyouter edge and a minimum in the portion closest to the spider 23.However, the largest proportion of the curved blade portion 44 isadjacent the spider 23, as is apparent from Fig. 6, and the concave faceof the portion 44 is opposed to the flow of air across the front surfaceof the blade. The result of this combination of factors is that theportion 44 is in effect of materially increased pitch as compared withthe central area 40 of the blade, and this compensates for the decreasedrelative surface speed of the portion 44 and enables it to propel morenearly the same volume of air per unit area thereof as the flat outerportion of the blade.

In addition to the increased total volumetric flow of air provided bythis blade construction, it is especially important that the curvedportion 44 produces an axial air flow in close proximity to the motor 20for maintained cooling action on the motor. This effect is alsocontributed to by the blade portion 41, since it acts, as a leading edgeof increased effective pitch which augments the total air delivery ofthe fan.

Similar operating conditions obtain when the drive motor is reversed torotate the blade assembly in the oppo site direction. The curved portion41 then becomes the trailing edge and operates in the same manner asdescribed for the portion 44' to produce a cooling flow of air in closeproximity to the motor, and the portion 44 similarly becomes a leadingedge of increased pitch to supplement the action of the trailing edgeportion 41. Theoretically, if the blade were perfectly symmetrical, withthe portions 41 and 44 of the same relative areas and effective pitch,identical flow conditions would exist for either direction of rotationof the motor, but this would require the overall depth of the fan casingto be greater than with the illustrated arrangement, and theconfiguration of the blade illustrated in Fig. 8 has given satisfactoryresults.

The construction and mode of operation of the blade assembly of theinvention are also of importance in connection with the reversing of thedrive motor during operation of the fan. More particularly, with eitherof the above types of reversible motor, it is necessary that the totalload on the motor approach the capacity of the motor if reversal is totake place. This result is obtained in accordance with the invention bythe action of the trailing edge portions of the blades, since inaddition to producing a cooling air flow close to the motor, they tendto create a braking force on the blade assembly such that if thereversing switch 35 is shifted during operation of the fan, the bladeassembly will immediately slow down and ultimately start rotation in theopposite direction. In contrast, if the trailing edge of the blade wereflat or curved in the same direction as the leading edge, the load onthe motor would in all probability not be sufficient to accomplishreversal during operation, and instead the motor would tend to continueto rotate in the same direc tion in spite of shifting of the reversingswitch.

Because of the important contribution of the edge portions of the bladeto the mode of operation of the fan as a whole, it is desirable thatthey be constructed with the maximum uniformity compatible withpracticability. This result is materially aided by the ribs or beads 45.In particular, these beads have a substantial stiffening effect on theblade which maintain the blade in the desired curved configuration. Thussince different batches of sheet metal have a tendency to vary inresiliency, if the curved edge portions were formed without the beads,there would be a correspondingly varied tendency for the blades tospring back after their curved edge portions have been formed therein,and this would create non-uniformity. The ribs 45, however, which extendtransversely of the radius of curvature of the respective portions 41and 44, resist the tendency of the sheet metal to change shape afterforming and thus make it possible to establish uniform predeterminedcurvature in all blades which will accurately represent the curvature ofthe dies by which the forming operation is carried out.

Cross reference is made to our application Serial No. 775,278 filedNovember 20, 1958 as a division of this application.

While the forms of apparatus herein described constitute preferredembodiments of the invention, it is to be understood that the inventionis not limited to these precise forms of apparatus, and that changes maybe made therein without departing from the scope of the invention whichis defined in the appended claims.

What is claimed is:

l. In combination, a reversible electric motor having a drive shaft, afan blade assembly mounted on said shaft and including a plurality ofblades, each of said blades comprising a main generally flat centerportion extending from the inner edge of said blade and including atleast a major portion of the outer edge thereof,

' said inner edge of said blade including an extended middle sectioncurved substantially concentrically with respect to said axis andopposite end sections curved in opposite directions to provide a pair oflobe portions each including portions of said inner edge and one sideedge of said blade, side portions of substantial axial pitch on bothsides of said blade extending in opposite portions forming major areasof the respective said side portions to provide leading and trailingedge portions on said blade of substantial area such that in eitherdirection of movement thereof one of said edge portions Will form atrailing edge portion of increased pitch with respect to said centerportion causing an axially directed airflow in close proximity to saidaxis for cooling said motor.

2. In combination, a reversible electric motor having a drive shaft, afan blade assembly mounted on said shaft and including a plurality ofblades, each of said blades comprising a main generally flat centerportion extending from the inner edge of said blade and including atleast a major portion of the outer edge thereof, side portions ofsubstantial axial pitch on both sides of said blade extending inopposite directions from said fiat center portion, the outer edges ofsaid side portions each including portions of said inner edge and oneside edge of said blade, said inner edge being curved ooaxially aboutsaid axis, and each of said side portions having the major area thereoflocated on the radially inner portion of said blade so that rotation ofsaid blade in either direction will cause an axially directedair flow inclose proximity to said axis for cooling said motor.

3. In combination, a reversible electric motor having a drive shaft, afan blade assembly mounted on said shaft and including a plurality ofblades, each of said blades comprising a main generally flat centerportion extending from the inner edge of said blade and including atleast a major portion of the outer edge thereof, said inner edge beingcurved substantially concentrically about said axis, side portions ofsubstantial axial pitch integrally formed on both sides of said bladeand extending in op posite directions from the plane of said centerportion, the outer edges of said side portions each including portionsof said inner edge and one side edge of said blade to define a pair oflobe portions located on the radially inner portion of said blade sothat rotation of said blade in either direction will cause an axiallydirected air flow in close proximity to the axis for cooling said motor,and an integral bead formed on each of said side portions and extendingsubstantially perpendicularly to the axis of curvature thereof from saidcenter portion of said blade to stiffen said side portions and saidlobes for maintaining the curved configuration thereof.

4. A fan blade of the character described comprising a main generallyflat center portion extending from the inner edge thereof and includingat least a major portion of the outer edge thereof, side portions ofsubstantial axial pitch on both sides of said blade extending inopposite directions from the plane of said center portion, the outeredges of said side portions each including portions of said inner edgeand one side edge of said blade, and each of said side portions havingthe major area thereof located in the radially inner portion of saidblade.

5. A fan blade of the character described comprising a main generallyflat center portion extending from the inner edge of said blade andincluding at least a major portion of the outer edge thereof, said inneredge of said blade including an extended middle section of concavecurvature and opposite end portions of convex curvature providing a pairof lobe portions each including portions of said inner edge and one sideedge of said blade, side portions of substantial axial pitch on bothsides of said blade extending in opposite directions from said bladecetner portion, and said lobe portions forming major areas of therespective said side portions.

References Cited in the file of this patent UNITED STATES PATENTS UNITEDSTATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 2 9l2 l59November l0 1959 Karl M. Ganger et a1.

It is hereby certified that error appears in the-printed specificationof the above numbered patent requiring correction and that the saidLetters Patent should read as corrected below.

Column 2, line 69 for "wtih" read with --g column 4 line 64L and column5, lines 10 and 26 after "shaft" and before the comma each occurrenceinsert adapted to rotate about a predetermined axis coinciding with theaxis of said motor same column 5', line 40, for "the axis." read saidaxis column 6, line 25 for "cetner" read center Signed and sealed this13th day of September 1960.

(SEAL) Attest:

KARL H. AXLINE ROBERT C. WATSON Attesting Officer Commissioner ofPatents

